The conversion tool, stadred application included in USFOS does not convert member-end releases. And so, very quickly, this manual conversion can become time-consuming, say, for hundred odd elements and above. Here are the things to pay attention to:

Elements: There are single elements, and then there are ranges.

Command: Start and end explicit commands introduce the need to manually sift to segregate in three sets, viz., elements with releases at start only, end only, and at both ends.

USFOS, on the other hand, uses a format of defining both start as well as end in one command like thus:

To convert end-releases from STAAD to USFOS, one needs to do the following:

Pick out range elements and list them first.

Convert ranges to full numerical list first, as USFOS does not recognise ranges like 686 TO 692.

Pick out single elements, and add them to the list above.

Once you have a full list of elements per two explicit release commands with START and END, like START MY MZ and END MY MZ, segregate them in to start only, end only and both end release list of elements.

Update (Nov 2016): I shared this code with Dr. Holmas of USFOS, and asked why stadred does not have the option of converting releases. He confirmed that release conversions were intentionally suppressed in stadred, as releases often cause problems in non-linear simulations. However, due to the uniqueness of the problem I was working on, he kindly sent me a working copy of stadred that also converts end-releases, for which I am indeed grateful.

Now, I have two ways to convert. The code above generates a somewhat concise instruction, but the process is semi-automatic, whereas the updated stadred copy I was given is fully automatic, but generates a much bigger file, since end-release instructions are generated per member.